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NodeJS 的模块</h3> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202231903248-1901890901.png" alt=""></p> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202122137859-1815223861.png" alt="img"></p> <h3 id="_3-fs-模块-文件读取模块"><a href="#_3-fs-模块-文件读取模块" class="header-anchor">#</a> 3. fs 模块(文件读取模块)</h3> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token comment">// 导入fs文件系统模块</span>
<span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>

<span class="token comment">// 读取文件</span>

fs<span class="token punctuation">.</span><span class="token function">readFile</span><span class="token punctuation">(</span><span class="token string">'./files/1.txt'</span><span class="token punctuation">,</span> <span class="token string">'utf8'</span><span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err<span class="token punctuation">,</span> datastr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token comment">// 失败的结果</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>err<span class="token punctuation">)</span>
  <span class="token comment">// 成功的结果</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>datastr<span class="token punctuation">)</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><ul><li>读取成功的判断</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>

<span class="token comment">// 读取文件</span>

fs<span class="token punctuation">.</span><span class="token function">readFile</span><span class="token punctuation">(</span><span class="token string">'./files/1.txt'</span><span class="token punctuation">,</span> <span class="token string">'utf8'</span><span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err<span class="token punctuation">,</span> datastr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>err <span class="token operator">===</span> <span class="token keyword">null</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'文件读取成功'</span> <span class="token operator">+</span> datastr<span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'文件读取失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h4 id="写入文件"><a href="#写入文件" class="header-anchor">#</a> 写入文件</h4> <div class="language-js line-numbers-mode"><pre class="language-js"><code>fs<span class="token punctuation">.</span><span class="token function">writeFile</span><span class="token punctuation">(</span>file<span class="token punctuation">,</span>data<span class="token punctuation">[</span><span class="token punctuation">,</span>options<span class="token punctuation">]</span><span class="token punctuation">,</span>callback<span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>options 编码格式，默认 utf8</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>
<span class="token comment">// 写入文件</span>
fs<span class="token punctuation">.</span><span class="token function">writeFile</span><span class="token punctuation">(</span><span class="token string">'./files/2.txt'</span><span class="token punctuation">,</span> <span class="token string">'666'</span><span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'写入文件失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'写入文件成功'</span> <span class="token operator">+</span> err<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><h4 id="文件路径"><a href="#文件路径" class="header-anchor">#</a> 文件路径</h4> <ul><li><p>原因：代码在运行时，<strong>会以执行 node 命令时所处的目录，动态拼接出文件的完整路径</strong></p></li> <li><p>解决方案</p> <ul><li>使用__dirname 代表当前文件所处的目录</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>

fs<span class="token punctuation">.</span><span class="token function">readFile</span><span class="token punctuation">(</span>__dirname <span class="token operator">+</span> <span class="token string">'/files/1.txt'</span><span class="token punctuation">,</span> <span class="token string">'utf8'</span><span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err<span class="token punctuation">,</span> datastr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'文件读取失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'文件读取成功'</span> <span class="token operator">+</span> datastr<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div></li> <li><p>下面介绍的 path 模块</p></li></ul> <h3 id="_4-path-模块"><a href="#_4-path-模块" class="header-anchor">#</a> 4. path 模块</h3> <ul><li><p><strong>将多个字符串拼接成一个完整的路径字符串</strong></p></li> <li><p>语法</p></li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code>path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span><span class="token punctuation">[</span><span class="token operator">...</span>paths<span class="token punctuation">]</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>...paths 路径片段序列</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'path'</span><span class="token punctuation">)</span>

<span class="token keyword">var</span> str <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span><span class="token string">'a/b/v'</span><span class="token punctuation">,</span> <span class="token string">'../'</span><span class="token punctuation">,</span> <span class="token string">'/m/n'</span><span class="token punctuation">,</span> <span class="token string">'c'</span><span class="token punctuation">)</span>

console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>str<span class="token punctuation">)</span> <span class="token comment">// a\b\m\n\c</span>

<span class="token keyword">var</span> str2 <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'./files/1.txt'</span><span class="token punctuation">)</span>

console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>str2<span class="token punctuation">)</span> <span class="token comment">// E:\\nodejs代码\day01\files\1.txt</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br></div></div><h4 id="获取文件路径的最后一个部分"><a href="#获取文件路径的最后一个部分" class="header-anchor">#</a> 获取文件路径的最后一个部分</h4> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'path'</span><span class="token punctuation">)</span>

<span class="token keyword">var</span> pathstr <span class="token operator">=</span> <span class="token string">'a/b/c/index.html'</span>

<span class="token comment">// 获取路径的最后一个部分</span>

<span class="token keyword">var</span> strName <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">basename</span><span class="token punctuation">(</span>pathstr<span class="token punctuation">)</span>

console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>strName<span class="token punctuation">)</span> <span class="token comment">// index.html</span>

<span class="token comment">// 添加文件扩展名参数，则返回值中不包含文件扩展名</span>

<span class="token keyword">var</span> strName2 <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">basename</span><span class="token punctuation">(</span>pathstr<span class="token punctuation">,</span> <span class="token string">'.html'</span><span class="token punctuation">)</span>

console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>strName2<span class="token punctuation">)</span> <span class="token comment">// index</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br></div></div><h4 id="获取一个路径名中扩展名的部分"><a href="#获取一个路径名中扩展名的部分" class="header-anchor">#</a> 获取一个路径名中扩展名的部分</h4> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'path'</span><span class="token punctuation">)</span>

<span class="token comment">// 定义一个文件存放路径</span>

<span class="token keyword">var</span> fpath <span class="token operator">=</span> <span class="token string">'a/b/c/index.html'</span>

<span class="token comment">// 获取文件路径中的扩展名</span>

<span class="token keyword">var</span> extName <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">extname</span><span class="token punctuation">(</span>fpath<span class="token punctuation">)</span>

console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>extName<span class="token punctuation">)</span> <span class="token comment">// .html</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br></div></div><h4 id="_8-一个时钟案例-拆分-html-文件中的-style-标签的内容和-script-标签内的内容"><a href="#_8-一个时钟案例-拆分-html-文件中的-style-标签的内容和-script-标签内的内容" class="header-anchor">#</a> 8.一个时钟案例（拆分 HTML 文件中的 style 标签的内容和 script 标签内的内容）</h4> <h3 id="思路"><a href="#思路" class="header-anchor">#</a> 思路</h3> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202231902734-1871964147.png" alt=""></p> <ul><li>代码实现</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token comment">// 导入fs模块</span>
<span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>
<span class="token comment">// 导入path模块</span>
<span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'path'</span><span class="token punctuation">)</span>

<span class="token comment">// 定义一个匹配style标签的正则表达式</span>
<span class="token comment">//  \s 代表任意空白字符，\S代表任意非空白字符，*代表匹配多次，结束标签中的&lt;\/style&gt; 的\用于转义，防止不合法</span>
<span class="token keyword">var</span> regStyle <span class="token operator">=</span> <span class="token regex"><span class="token regex-delimiter">/</span><span class="token regex-source language-regex">&lt;style&gt;[\s\S]*&lt;\/style&gt;</span><span class="token regex-delimiter">/</span></span>

<span class="token comment">// 定义一个匹配script标签内容的正则表达式</span>
<span class="token keyword">var</span> regScript <span class="token operator">=</span> <span class="token regex"><span class="token regex-delimiter">/</span><span class="token regex-source language-regex">&lt;script&gt;[\s\S]*&lt;\/script&gt;</span><span class="token regex-delimiter">/</span></span>

<span class="token comment">// 获取files下index.html文件的字符串内容</span>

<span class="token keyword">var</span> htmlPath <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'./index.html'</span><span class="token punctuation">)</span>

fs<span class="token punctuation">.</span><span class="token function">readFile</span><span class="token punctuation">(</span>htmlPath<span class="token punctuation">,</span> <span class="token string">'utf8'</span><span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err<span class="token punctuation">,</span> datastr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'读取文件失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'读取文件成功'</span><span class="token punctuation">)</span>

    <span class="token comment">// 存放文件字符串</span>

    <span class="token keyword">var</span> htmlStr <span class="token operator">=</span> datastr
    <span class="token function">resloveCss</span><span class="token punctuation">(</span>htmlStr<span class="token punctuation">)</span>
    <span class="token function">resloveJs</span><span class="token punctuation">(</span>htmlStr<span class="token punctuation">)</span>
    <span class="token function">resloveHtml</span><span class="token punctuation">(</span>htmlStr<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>

<span class="token comment">// 将内嵌的style标签的内容写入css文件</span>
<span class="token keyword">function</span> <span class="token function">resloveCss</span><span class="token punctuation">(</span><span class="token parameter">htmlStr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token comment">// 匹配正则表达式</span>

  <span class="token keyword">var</span> styleStr <span class="token operator">=</span> regStyle<span class="token punctuation">.</span><span class="token function">exec</span><span class="token punctuation">(</span>htmlStr<span class="token punctuation">)</span>

  <span class="token comment">// 将标签名去除</span>
  <span class="token comment">// console.log(styleStr);</span>

  <span class="token keyword">var</span> cssStr <span class="token operator">=</span> styleStr<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span><span class="token string">'&lt;style&gt;'</span><span class="token punctuation">,</span> <span class="token string">''</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span><span class="token string">'&lt;/style&gt;'</span><span class="token punctuation">,</span> <span class="token string">''</span><span class="token punctuation">)</span>

  <span class="token keyword">var</span> cssPath <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'./files/index.css'</span><span class="token punctuation">)</span>
  fs<span class="token punctuation">.</span><span class="token function">writeFile</span><span class="token punctuation">(</span>cssPath<span class="token punctuation">,</span> cssStr<span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">return</span> console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'写入文件失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
      console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'写入index.css成功'</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>

<span class="token comment">// 将内嵌script标签内的内容写入 js文件中</span>
<span class="token keyword">function</span> <span class="token function">resloveJs</span><span class="token punctuation">(</span><span class="token parameter">htmlStr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">var</span> scriptStr <span class="token operator">=</span> regScript<span class="token punctuation">.</span><span class="token function">exec</span><span class="token punctuation">(</span>htmlStr<span class="token punctuation">)</span>

  <span class="token keyword">var</span> jsStr <span class="token operator">=</span> scriptStr<span class="token punctuation">[</span><span class="token number">0</span><span class="token punctuation">]</span><span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span><span class="token string">'&lt;script&gt;'</span><span class="token punctuation">,</span> <span class="token string">''</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span><span class="token string">'&lt;/script&gt;'</span><span class="token punctuation">,</span> <span class="token string">''</span><span class="token punctuation">)</span>

  <span class="token keyword">var</span> jsPath <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'./files/index.js'</span><span class="token punctuation">)</span>
  fs<span class="token punctuation">.</span><span class="token function">writeFile</span><span class="token punctuation">(</span>jsPath<span class="token punctuation">,</span> jsStr<span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">return</span> console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'写入文件失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
      console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'写入index.js成功'</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>

<span class="token comment">// 将html文件中的内嵌式style 和 script 标签的内容替换为 外联式的引用</span>

<span class="token keyword">function</span> <span class="token function">resloveHtml</span><span class="token punctuation">(</span><span class="token parameter">htmlStr</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token keyword">var</span> newHtml <span class="token operator">=</span> htmlStr
    <span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span>regStyle<span class="token punctuation">,</span> <span class="token string">&quot;&lt;link rel='stylesheet' href='./index.css'/&gt;&quot;</span><span class="token punctuation">)</span>
    <span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span>regScript<span class="token punctuation">,</span> <span class="token string">&quot;&lt;script src='./index.js'&gt;&lt;/script&gt;&quot;</span><span class="token punctuation">)</span>
  <span class="token keyword">var</span> newpath <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'./files/index.html'</span><span class="token punctuation">)</span>
  fs<span class="token punctuation">.</span><span class="token function">writeFile</span><span class="token punctuation">(</span>newpath<span class="token punctuation">,</span> newHtml<span class="token punctuation">,</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">err</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">return</span> console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'html文件写入失败'</span> <span class="token operator">+</span> err<span class="token punctuation">.</span>message<span class="token punctuation">)</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
      console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'html文件写入成功'</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br><span class="line-number">58</span><br><span class="line-number">59</span><br><span class="line-number">60</span><br><span class="line-number">61</span><br><span class="line-number">62</span><br><span class="line-number">63</span><br><span class="line-number">64</span><br><span class="line-number">65</span><br><span class="line-number">66</span><br><span class="line-number">67</span><br><span class="line-number">68</span><br><span class="line-number">69</span><br><span class="line-number">70</span><br><span class="line-number">71</span><br><span class="line-number">72</span><br><span class="line-number">73</span><br><span class="line-number">74</span><br><span class="line-number">75</span><br><span class="line-number">76</span><br><span class="line-number">77</span><br><span class="line-number">78</span><br><span class="line-number">79</span><br><span class="line-number">80</span><br><span class="line-number">81</span><br><span class="line-number">82</span><br><span class="line-number">83</span><br></div></div><h3 id="_5-http-模块"><a href="#_5-http-模块" class="header-anchor">#</a> 5. http 模块</h3> <ul><li>创建 web 服务器</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> http <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'http'</span><span class="token punctuation">)</span>
<span class="token keyword">const</span> server <span class="token operator">=</span> http<span class="token punctuation">.</span><span class="token function">createServer</span><span class="token punctuation">(</span><span class="token punctuation">)</span>

server<span class="token punctuation">.</span><span class="token function">on</span><span class="token punctuation">(</span><span class="token string">'request'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter">req<span class="token punctuation">,</span> res</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
  <span class="token comment">// 有关客户端的字符串</span>
  <span class="token keyword">var</span> str <span class="token operator">=</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">你请求的url地址为</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>req<span class="token punctuation">.</span>url<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">,请求方式为</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>req<span class="token punctuation">.</span>method<span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span>

  <span class="token comment">// 将该字符串作为响应消息发给客户端,并结束这次请求</span>

  res<span class="token punctuation">.</span><span class="token function">setHeader</span><span class="token punctuation">(</span><span class="token string">'Content-Type'</span><span class="token punctuation">,</span> <span class="token string">'text/html; charset=utf-8'</span><span class="token punctuation">)</span>

  res<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span>str<span class="token punctuation">)</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>

server<span class="token punctuation">.</span><span class="token function">listen</span><span class="token punctuation">(</span><span class="token number">80</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'http server running at http://10.152.242.223'</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br></div></div><h4 id="根据不同-url-响应不同的内容"><a href="#根据不同-url-响应不同的内容" class="header-anchor">#</a> 根据不同 url 响应不同的内容</h4> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token comment">// 导入http，fs，path</span>

<span class="token keyword">const</span> fs <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'fs'</span><span class="token punctuation">)</span>
<span class="token keyword">const</span> http <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'http'</span><span class="token punctuation">)</span>
<span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'path'</span><span class="token punctuation">)</span>

<span class="token comment">// 创建服务器实例</span>

<span class="token keyword">var</span> server <span class="token operator">=</span> http<span class="token punctuation">.</span><span class="token function">createServer</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
<span class="token comment">// 监听服务器实例</span>
server<span class="token punctuation">.</span><span class="token function">on</span><span class="token punctuation">(</span><span class="token string">'request'</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter">req<span class="token punctuation">,</span> res</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
  <span class="token keyword">var</span> url <span class="token operator">=</span> req<span class="token punctuation">.</span>url

  <span class="token comment">// 进行路径拼接</span>
  <span class="token keyword">var</span> pathStr <span class="token operator">=</span> <span class="token string">''</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>url <span class="token operator">===</span> <span class="token string">'/'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">// 默认是首页地址</span>
    pathStr <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'/clock/index.html'</span><span class="token punctuation">)</span>
  <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
    <span class="token comment">// 请求css，js时拼接clock目录</span>
    pathStr <span class="token operator">=</span> path<span class="token punctuation">.</span><span class="token function">join</span><span class="token punctuation">(</span>__dirname<span class="token punctuation">,</span> <span class="token string">'/clock'</span><span class="token punctuation">,</span> url<span class="token punctuation">)</span>
  <span class="token punctuation">}</span>

  fs<span class="token punctuation">.</span><span class="token function">readFile</span><span class="token punctuation">(</span>pathStr<span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token parameter">err<span class="token punctuation">,</span> datastr</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>err<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token comment">// 读取到不存在的文件</span>
      <span class="token keyword">return</span> res<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span><span class="token string">'404 not found!'</span><span class="token punctuation">)</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
      <span class="token comment">// res.setHeader('Content-Type', 'text/html; charset=utf-8')</span>
      res<span class="token punctuation">.</span><span class="token function">end</span><span class="token punctuation">(</span>datastr<span class="token punctuation">)</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>

<span class="token comment">// 开启服务器</span>

server<span class="token punctuation">.</span><span class="token function">listen</span><span class="token punctuation">(</span><span class="token number">80</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'http server running at http://10.152.242.223'</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br></div></div><h3 id="_6-模块化"><a href="#_6-模块化" class="header-anchor">#</a> 6.模块化</h3> <h4 id="_6-1-module-exports-对象"><a href="#_6-1-module-exports-对象" class="header-anchor">#</a> 6.1 module.exports 对象</h4> <ul><li>在自定义模块中，<strong>可以使用 module.exports 对象，将模块内的成员共享出去，供外界使用</strong></li> <li><strong>使用 require()方法导入自定义模块时，得到的就是 module.exports 所指向的对象</strong></li></ul> <h5 id="示例"><a href="#示例" class="header-anchor">#</a> 示例</h5> <ul><li>自定义模块.js</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token comment">// 在module.exports对象上挂载 username属性</span>

module<span class="token punctuation">.</span>exports<span class="token punctuation">.</span>username <span class="token operator">=</span> <span class="token string">'zs'</span>

<span class="token comment">// 在module.exports对象上挂载sayHello()方法</span>

module<span class="token punctuation">.</span>exports<span class="token punctuation">.</span><span class="token function-variable function">sayHello</span> <span class="token operator">=</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'hello!'</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span>

<span class="token keyword">const</span> age <span class="token operator">=</span> <span class="token number">20</span>
module<span class="token punctuation">.</span>exports<span class="token punctuation">.</span>age <span class="token operator">=</span> age
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br></div></div><ul><li>测试.js</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> zdy <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'./06.自定义模块'</span><span class="token punctuation">)</span>

console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>zdy<span class="token punctuation">)</span> <span class="token comment">// {username:'zs',sayHello:[Function(anoymous)],age:20}</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div><h4 id="注意点"><a href="#注意点" class="header-anchor">#</a> 注意点</h4> <ul><li><p>使用 require()方法导入模块时，<strong>导入的结果，永远以 module.exports 指向的对象为准</strong></p></li> <li><p>原因：exports 对象和 module.exports 一开始存放者一样的地址，如果修改 exports 内的地址，而 moudle.exports 的地址部分是改变，暴露的还是 module.exports 指向的对象，反过来也是如此</p></li></ul> <h3 id="_6-模块加载机制"><a href="#_6-模块加载机制" class="header-anchor">#</a> 6. 模块加载机制</h3> <h4 id="_6-1-模块优先从缓存中加载"><a href="#_6-1-模块优先从缓存中加载" class="header-anchor">#</a> 6.1 模块优先从缓存中加载</h4> <ul><li>模块在第一次被加载时里面的代码会被执行，加载后模块被缓存，多次调用 require（）方法不会导致模块的代表被多次执行</li></ul> <h4 id="示例-2"><a href="#示例-2" class="header-anchor">#</a> 示例</h4> <ul><li>自定义模块 4</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code>console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'hello'</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>测试自定义模块 4</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'./17.自定义模块4'</span><span class="token punctuation">)</span>

<span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'./17.自定义模块4'</span><span class="token punctuation">)</span>

<span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'./17.自定义模块4'</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br></div></div><ul><li>效果图</li></ul> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202231902144-1911852216.png" alt=""></p> <h4 id="_6-2-内置模块的加载机制"><a href="#_6-2-内置模块的加载机制" class="header-anchor">#</a> 6.2 内置模块的加载机制</h4> <ul><li>内置模块是由 Node.js 官方提供的，内置模块的加载优先级最高</li> <li>例如，require（'fs'）始终返回内置的 fs 模块，即使在 node_modules 目录下有名字相同的包也叫做 fs</li></ul> <h4 id="_6-3-自定义模块的加载机制"><a href="#_6-3-自定义模块的加载机制" class="header-anchor">#</a> 6.3 自定义模块的加载机制</h4> <ul><li>使用 require()加载自定义模块时，必须指定以./或../开头的路径标识符，在加载自定义模块时，如果没有指定./或../这样的路径标识符，则 node 会把他当作内置模块或第三方模块进行加载</li></ul> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202231901646-1760622625.png" alt=""></p> <h4 id="_6-4-第三方模块的加载机制"><a href="#_6-4-第三方模块的加载机制" class="header-anchor">#</a> 6.4 第三方模块的加载机制</h4> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202231901221-853863495.png" alt=""></p> <h4 id="_6-5-目录作为模块"><a href="#_6-5-目录作为模块" class="header-anchor">#</a> 6.5 目录作为模块</h4> <p><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230202231900549-669332419.png" alt=""></p> <h3 id="_7-express"><a href="#_7-express" class="header-anchor">#</a> 7 express</h3> <div class="language-js line-numbers-mode"><pre class="language-js"><code>npm i express@<span class="token number">4.17</span><span class="token number">.1</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>创建最基本的 web 服务器</li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token keyword">const</span> express <span class="token operator">=</span> <span class="token function">require</span><span class="token punctuation">(</span><span class="token string">'express'</span><span class="token punctuation">)</span>

<span class="token keyword">const</span> app <span class="token operator">=</span> <span class="token function">express</span><span class="token punctuation">(</span><span class="token punctuation">)</span>

app<span class="token punctuation">.</span><span class="token function">listen</span><span class="token punctuation">(</span><span class="token number">80</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=&gt;</span> <span class="token punctuation">{</span>
  console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span><span class="token string">'express server running at http:127.0.0.1'</span><span class="token punctuation">)</span>
<span class="token punctuation">}</span><span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br></div></div></div></div>  <div class="page-edit"><div class="edit-link"><a href="https://github.com/linxin1123/vuepress-blog/edit/master/docs/08.面试/01.蓝桥杯备战/04.NodeJs复习-cnblog.md" target="_blank" rel="noopener noreferrer">编辑</a> <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></div> <!----> <div class="last-updated"><span class="prefix">上次更新:</span> <span class="time">2023/02/17, 11:29:32</span></div></div> <div class="page-nav-wapper"><div class="page-nav-centre-wrap"><a href="/pages/e4078d/" class="page-nav-centre page-nav-centre-prev"><div class="tooltip">ajax复习</div></a> <a href="/pages/54f5cc/" class="page-nav-centre page-nav-centre-next"><div class="tooltip">HTML篇(一)-cnblog</div></a></div> <div class="page-nav"><p class="inner"><span class="prev">
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